Chain saws are popular and useful tools that are utilized by many industries and individual users. Probably the most common use of the chain saw is in cutting of wood products ranging from felling of trees, trimming branches from trees and sawing the logs resulting from the trees into lengths. Chain saws have also been applied to other industries such as the concrete or construction industry wherein the chain saw is utilized to saw such items as concrete and/or stone.
Basically the chain saw has a power head, a guide bar and an endless saw chain (a loop of chain). The guide bar is mounted to the power head and the endless chain is entrained around the guide bar with the chain having a drive link tang fitting in a groove of the guide bar. The saw chain is driven by a drive sprocket of the power head to propel the saw chain around the guide bar.
There are many different types of saw chain having reference to the gauge of the chain (the width of the drive link tang which must be fit to the guide bar groove) and pitch (the distance between rivets which must be fit to a particular sprocket type, e.g., a nose sprocket provided on the nose end of the guide bar and the drive sprocket of the power head).
The guide bars, drive sprockets and saw chain are replaceable since they are subject to wear and/or damage when in use. New guide bars most often have details imprinted, painted, and/or stenciled on the side surfaces of the guide bar to enable a user to match the bar to a particular chain and/or sprocket.
The guide bar when in use is generally subjected to a harsh environment. The guide bar of the chain saw will, for example, be traveling through the kerf produced by the saw chain and in the process the side surfaces of the guide bar will be rubbing against the material which is being sawn. Additionally, the guide bar is subjected to the lubricating oil which lubricates the guide bar and chain and will further be subjected to moisture, dirt and other items. The markings on the guide bar will over time through use of the guide bar generally be rubbed off or worn away.
When the details have been worn off the guide bar it is often difficult for a user (particularly a novice user) to identify a correct replacement guide bar and/or saw chain that is matched to each other and to the power head of the chain saw. The guide bar or saw chain may appear to be of the correct type however there are many different types of guide bars and saw chains that will appear similar to the untrained eye and the task of locating a desired replacement bar or chain can often be a frustrating experience particularly to a novice user.